diff options
Diffstat (limited to 'sql-common/pack.c')
| -rw-r--r-- | sql-common/pack.c | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/sql-common/pack.c b/sql-common/pack.c new file mode 100644 index 00000000..de821f08 --- /dev/null +++ b/sql-common/pack.c @@ -0,0 +1,210 @@ +/* Copyright (c) 2000-2003, 2007 MySQL AB + Use is subject to license terms + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; version 2 of the License. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */ + +#include <my_global.h> +#include <mysql_com.h> +#include <mysql.h> + +/* Get the length of next field. Change parameter to point at fieldstart */ +ulong net_field_length(uchar **packet) +{ + reg1 uchar *pos= (uchar *)*packet; + if (*pos < 251) + { + (*packet)++; + return (ulong) *pos; + } + if (*pos == 251) + { + (*packet)++; + return NULL_LENGTH; + } + if (*pos == 252) + { + (*packet)+=3; + return (ulong) uint2korr(pos+1); + } + if (*pos == 253) + { + (*packet)+=4; + return (ulong) uint3korr(pos+1); + } + (*packet)+=9; /* Must be 254 when here */ + return (ulong) uint4korr(pos+1); +} + +/* The same as above but returns longlong */ +my_ulonglong net_field_length_ll(uchar **packet) +{ + uchar *pos= *packet; + if (*pos < 251) + { + (*packet)++; + return (my_ulonglong) *pos; + } + if (*pos == 251) + { + (*packet)++; + return (my_ulonglong) NULL_LENGTH; + } + if (*pos == 252) + { + (*packet)+=3; + return (my_ulonglong) uint2korr(pos+1); + } + if (*pos == 253) + { + (*packet)+=4; + return (my_ulonglong) uint3korr(pos+1); + } + DBUG_ASSERT(*pos == 254); + (*packet)+=9; /* Must be 254 when here */ + return (my_ulonglong) uint8korr(pos+1); +} + +my_ulonglong safe_net_field_length_ll(uchar **packet, size_t packet_len) +{ + uchar *pos= *packet; + if (packet_len < 1) + goto err; + if (*pos < 251) + { + (*packet)++; + return (my_ulonglong) *pos; + } + if (*pos == 251) + { + (*packet)++; + return (my_ulonglong) NULL_LENGTH; + } + if (*pos == 252) + { + if (packet_len < 3) + goto err; + (*packet)+=3; + return (my_ulonglong) uint2korr(pos+1); + } + if (*pos == 253) + { + if (packet_len < 4) + goto err; + (*packet)+=4; + return (my_ulonglong) uint3korr(pos+1); + } + if (packet_len < 9 || *pos != 254) + goto err; + (*packet)+=9; + return (my_ulonglong) uint8korr(pos+1); +err: + *packet = NULL; + return 0; +} + +/* + Store an integer with simple packing into a output package + + SYNOPSIS + net_store_length() + packet Store the packed integer here + length integers to store + + NOTES + This is mostly used to store lengths of strings. + + RETURN + Position in 'packet' after the packed length +*/ + +uchar *net_store_length(uchar *packet, ulonglong length) +{ + if (length < 251) + { + *packet= (uchar) length; + return packet+1; + } + /* 251 is reserved for NULL */ + if (length < 65536) + { + *packet++=252; + int2store(packet, (uint) length); + return packet+2; + } + if (length < 16777216) + { + *packet++=253; + int3store(packet, (ulong) length); + return packet+3; + } + *packet++=254; + int8store(packet,length); + return packet+8; +} + +uchar *safe_net_store_length(uchar *packet, size_t packet_len, ulonglong length) +{ + if (length < 251) + { + if (packet_len < 1) + return NULL; + *packet= (uchar) length; + return packet+1; + } + /* 251 is reserved for NULL */ + if (length < 65536) + { + if (packet_len < 3) + return NULL; + *packet++=252; + int2store(packet, (uint) length); + return packet+2; + } + if (length < 16777216) + { + if (packet_len < 4) + return NULL; + *packet++=253; + int3store(packet, (ulong) length); + return packet+3; + } + if (packet_len < 9) + return NULL; + *packet++=254; + int8store(packet,length); + return packet+8; +} + + +/** + The length of space required to store the resulting length-encoded integer + for the given number. This function can be used at places where one needs to + dynamically allocate the buffer for a given number to be stored as length- + encoded integer. + + @param num [IN] the input number + + @return length of buffer needed to store this number [1, 3, 4, 9]. +*/ + +uint net_length_size(ulonglong num) +{ + if (num < (ulonglong) 251LL) + return 1; + if (num < (ulonglong) 65536LL) + return 3; + if (num < (ulonglong) 16777216LL) + return 4; + return 9; +} |